It's a familiar tableau in American presidential campaigns: The party out of power runs against China policy and promises a tough new approach; the administration in power does its best with an unsatisfactory relationship. Mitt Romney is no different. His website proclaims:

"It is time to end the Obama administration's acquiescence to the one-way arrangements the Chinese have come to enjoy. We need a fresh and fearless approach to that trade relationship. Our first priority must be to put on the table all unilateral actions within our power to ensure that the Chinese adhere to existing agreements. Anyone with business experience knows that you can succeed in a negotiation only if you are willing to walk away. If we want the Chinese to play by the rules, we must be willing to say 'no more' to a relationship that too often benefits them and harms us."

Once alarmed by this sort of rhetoric, China now just sits back and waits for election season to pass. In 1979 Ronald Reagan accused Jimmy Carter of humiliating Taiwan and promised to renew official relations. In 1992 Bill Clinton proposed raising tariffs on Chinese goods to force the "butchers of Beijing" to reshape the Chinese political system. Romney's rhetoric this autumn focuses on economics rather than on high strategy or human rights, but promises an equally drastic reshaping of trade with China.

Once in office, Reagan and Clinton glumly concluded that the big changes they had promised would do more harm than good, and quietly dropped them.

Would a Romney administration be any different? Perhaps - but if there's to be a real breach, it will probably come from a different source.

Step back a bit for some perspective. American-Chinese ties have been uneasy for a generation. This is probably inevitable, given the mesh of prickly issues surrounding the relationship - an unfriendly accommodation on the status of Taiwan, an alloyed cooperation over opposing North Korea's nuclear program, growing concerns about muscular Chinese approaches to maritime sovereignty, as well as the intellectual property piracy and currency issues that Romney raises, or concerns over cyber-espionage and hacking of US government and company computers. And an often bad relationship may have structural reasons to worsen.

In a remarkable Brookings Institution dialogue, Addressing U.S.-China Strategic Distrust, Chinese scholar Wang Jisi describes a mindset among Chinese government and scholarly elites that could easily push the relationship into crisis. He describes a consensus, or near-consensus, in Beijing that the structure of global politics makes a basically cooperative relationship all but impossible:

"America's financial disorder, alarming deficit and unemployment rate, slow economic recovery and political polarization are viewed as but a few indicators that the United States is headed toward decline. ... It is strongly believed in China that the ultimate goal of the United States in world affairs is to maintain its hegemony and dominance and, as a result, Washington will attempt to prevent the emerging powers, in particular China, from achieving their goals and enhancing their stature."

If Wang's description is accurate - with a confident and suspicious Chinese elite, viewing the United States as inevitably driven to oppose Chinese goals based on a fear of losing power, and basing their own decisions on this premise - then the future is likely to be difficult regardless of American policy choices.

But if American choices over the next year are the decisive factor, then the future is likely to be much like the past two decades - mixing suspicion with cooperation, mutual economic dependence with arguments over policy.

A recent in-depth study of American opinion on China, conducted this summer by the Pew Research Center, reveals a public sympathetic to abstract calls for "toughness," but uninterested in a fight. Pew found that 45 percent of Americans want a "tougher" China policy, but 39 percent say the Obama administration's approach is "about right." Likewise a very large majority of the public, 86 percent, considers it "very important" or "somewhat important" to be tough with China on economic issues; but an even larger majority of 88 percent maintains that it is "very important" or "somewhat important" to build a strong relationship with China. The picture, then, is of a public that's not totally satisfied with policy, but by no means wants to walk away.

In practice - though with one big exception - the actual proposals that follow Romney's threat to walk away fall far short not only of "fresh and fearless," but of policy that differs much from the president's. Romney's campaign document includes five points:

- A pledge to "designate China a currency manipulator and impose countervailing duties";

- A promise to spend more money for the US Customs Service to inspect imports;

- A similar promise to spend more money through the US Trade Representative Office to file lawsuits at the World Trade Organization;

- A pledge to "use unilateral and multilateral punitive measures to deter unfair Chinese practices," which is ambiguous but appears to mean enforcing anti-dumping laws;

- An end to US government procurement from China until China commits to join the WTO's Government Procurement Agreement.

Most of this sounds modest and technical - and it is. More striking still, it's mainly a list the Obama administration has already accomplished. A quick trawl through WTO dispute filings, agency budgets and Commerce Department trade litigation show that since 2009 the Obama administration has added trade enforcement staff, filed eight WTO cases against Chinese policies in four years - one more than the seven the Bush administration did over its eight years in office, and imposed 39 anti-dumping and countervailing duty penalties on Chinese imports, which is not far below the 50 the Bush administration did over eight years.

In effect, most of Romney's proposals are promises to continue the Obama administration's policy. The exception is Romney's plan to declare China a "currency manipulator" and impose an across-the-board "countervailing duty" - a big tariff - on Chinese goods.

This is almost identical to the promise Bill Clinton made to withdraw most-favored nation tariff status in 1992. The average US tariff on Chinese goods is about 3 percent, and last year we bought $400 billion in goods from China. A 20 percent countervailing duty - to choose a figure matching common guesses at the degree of currency misalignment - would at face value mean an $80 billion penalty. This is nearly three times the size of the entire $29 billion US national tariff system, easily enough to spark a genuine trade war, a financial shock and an irreparable breach in the larger relationship with China.

The prospect is perhaps not so much "fearless" as "reckless." In the end, even if he wins, the measure seems unlikely to be taken - just as Clinton and Reagan rethought their campaign rhetoric after taking office.

So, should observers, particularly those in China, then discount the campaign's China debate as simply a tired repeat of the past? Not entirely - fearless but ill-advised promises often can lead their authors into traps of credibility and face, and human beings often miscalculate. But they should at least be skeptical. And if Chinese scholar Wang is right, the greater possibility of a permanent breach looks likely to come from the other side of the Pacific.